<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container{
            width: 400px;
            border: 5px solid yellow;
            background-color: yellow;
        }

        .clearfix::after{
            content: '';
            display: block;
            clear: both;
        }

        .left-column{
            float: left;
            width: 140px;
            height: 200px;
            background-color: pink;
            margin-right: 20px;
        }

        .right-column{
            float: right;
            width: 240px;
            height: 200px;
            background-color: cyan;
        }
    </style>
</head>
<body>
    <div class="clearfix container">
        <div class="left-column"></div>
        <div class="right-column"></div>
    </div>
</body>
</html>